The present invention relates to a novel organopolysiloxane compound and a composition containing the same as a principal ingredient suitable for use as a fabric-finishing agent or waterproofing agent capable of imparting excellent softness in touch feeling to a fabric material and resistance against yellowing as well as waterproofness to cellulosic materials including paperboards treated therewith to serve as a covering of plasterboards.
It is an established prior art technology that fabric materials in general can be imparted with softness and smoothness or slipperiness in touch feeling by a treatment with a fabric-finishing agent containing an organopolysiloxane compound including dimethylpolysiloxanes, epoxy group-containing organopolysiloxanes, aminoalkyl group-containing organopolysiloxanes and the like. In respect of the high softness in touch feeling imparted to the fabric material treated with the fabric-finishing agent, those formulated with an aminoalkyl-containing organopolysiloxane are preferred and those of which the aminoalkyl group in the aminoalkyl-containing organopolysiloxane compound is a 3-aminopropyl group --C.sub.3 H.sub.6 NH.sub.2, 3--(N-2-aminoethylamino)propyl group --C.sub.3 H.sub.6 NHC.sub.2 H.sub.4 NH.sub.2 and the like are the most widely employed for the purpose (see Japanese Patent Publications 48-1480, 54-43614 and 57-43673, Japanese Patent Kokai 60-185879, 60-185880 and 64-61576 and elsewhere).
Aminoalkyl group-containing diorganopolysiloxanes, when used as the principal ingredient of silicone-based fabric-finishing agent, however, have a very serious disadvantage that, when a fabric material is treated with a fabric-finishing agent containing such an organopolysiloxane, the aminoalkyl groups are liable to cause degradation by the influences of heat in the drying process after the treatment or by the influences of ultraviolet light in the sunlight falling on the fabric material in the lapse of time. This problem is particularly serious when the fabric material subjected to a fabric-finishing treatment is a white-colored or light-colored one because yellowing of the fabric material proceeds as a consequence of the degradation of the aminoalkyl groups.
As a countermeasure to prevent yellowing of fabric materials treated with an aminoalkyl group-containing organopolysiloxane-based fabric-finishing agent, proposals are made for the modification of the amino groups by the reaction of the organopolysiloxane with a monocarboxylic acid anhydride or chloride (Japanese Patent Kokai 57-101076), with an epoxy compound (Japanese Patent Kokai 59-179884), with a higher fatty acid (Japanese Patent Kokai 1-306683) and with an organic carbonate compound (Japanese Patent Kokai 2-47371).
Although improvements to some extent can be expected for yellowing prevention of fabric materials treated with an aminoalkyl group-containing organopolysiloxane-based fabric-finishing agent by the application of the above mentioned prior art methods as compared with unmodified aminoalkyl group-containing organopolysiloxanes, the effectiveness is still quite insufficient and rather an adverse influence is caused in the softness and slipperiness of the fabric materials treated therewith.
Besides the above mentioned application of an organopolysiloxane-containing composition as a fabric-finishing agent, organopolysiloxane compounds are employed as a principal ingredient in a waterproofing agent for various kinds of cellulosic materials including paperboards. Cellulosic materials of a class in which a waterproofing treatment is of great significance are paperboards as a covering layer in a so-called plasterboard consumed in large quantities as a building material not only in living houses but also in office buildings. As is known, a plasterboard has a layered structure consisting of a core board of hydrated and hardened gypsum sandwiched between two multilayer-sheeted paperboards each adhesively bonded to one of the surfaces of the core board. The paperboard used in plasterboards must satisfy several requirements that the mechanical strength of the paperboard per se is high enough, that the paperboard has good moisture-proofness, that the paperboard exhibits small dimensional changes between the dried and moistened states, that good adhesive bonding can be obtained between the core board of hydrated gypsum and the paperboard, that paperboard has moderate moisture permeability, and so on, of which the requirements for moistureproofness and dimensional stability by moistening are particularly important.
It is conventionally practiced in the industry of plasterboards that the surface of a paperboard is subjected to a waterproofing treatment by using a waterproofing agent when the paperboard is desired to have improved moisture resistance and dimensional stability by moistening. Most of the waterproofing agents currently under use for this purpose contain, as a principal ingredient, a silicone oil including dimethylsilicone oils and various types of modified silicone oils which, in most cases, are used in the form of an aqueous emulsion to prepare a water-base waterproofing agent.
Use of an epoxy-modified silicone oil, such as those disclosed in U.S. Pat. No. 3,389,042, in the waterproofing treatment of paperboard materials is also not quite satisfactory for solving the problems. Use of a mercapto group-containing silicone oil, such as those disclosed in Japanese Patent Publication 56-47994, as a principal ingredient in a silicone-based waterproofing agent has a serious problem of a strongly offensive odor as an inherent property of mercapto compounds in general to cause great deterioration of the working environment even though a substantial improvement can be obtained thereby in the waterproofing effect. The inventors previously made a proposal for an improved method of waterproofing treatment of paperboards by using an aqueous emulsion of an aminoalkyl group-containing organopolysiloxane disclosed in Japanese Patent Kokai 5-42637. This method, however, is not quite suitable for practical applications due to a relatively long time before appearance of a full waterproofing effect even though the improvement ultimately accomplished therewith is quite substantial.